On Tuesday, Oz, host of The Dr. Oz Show, was under fire from senators about some of his claims about health products.

Sen. Claire McCaskill, chairwoman of the Subcommittee on Consumer Protection, Product Safety and Insurance, questioned him on products such as green coffee beans and garcinia cambogia—both endorsed on his show, and both now associated with weight-loss scams. McCaskill said she was discouraged by the “false hope” his claims give viewers and questioned his role “intentional or not, in perpetuating these scams.”

“I don’t get why you need to say this stuff when you know it’s not true. When you have this amazing megaphone, why would you cheapen your show?” she asked.

Oz admitted that he sometimes uses “flowery language” to describe products on his show, but believes in the products and has promoted them to family members.

“My job, I feel, on the show is to be a cheerleader for the audience, and when they don’t think they have hope, when they don’t think they can make it happen, I want to look, and I do look everywhere, including in alternative healing traditions, for any evidence that might be supportive to them,” Oz said. He would like to stop manufacturers from using his name in their claims, he said.

“To not have the conversation about supplements at all however would be a disservice to the viewer,” Oz said in a statement after the hearing. “In addition to exercising an abundance of caution in discussing promising research and products in the future, I look forward to working with all those present today in finding a way to deal with the problems of weight loss scams.”

Let’s take a look at a few of the products Oz has endorsed and/or explored on his show.

Green coffee beans: A 2012 study found that chlorogenic acid, the main ingredient in green coffee beans, helped 16 people lose an average of 18 pounds over a 22-week span, but another study in mice found it boosted insulin resistance. Other studies have shown it can help people lose weight, but they were small studies that only took place over a short period of time.

Garcinia cambogia: Oz hailed this as “a revolutionary fat buster” on his show, but studies have yet to provide solid evidence that it works as a weight loss tool. Some websites claimed that Women’s Health magazine endorsed the product.

Raspberry ketone: Oz’s website says that studies have shown raspberry ketone can help people shed pounds when taken with a healthy diet and exercise regimen. Supporters claim that raspberry ketone causes cell fat to break up and burn faster.